Heater with alert indicator

ABSTRACT

A heater assembly includes heating element for generating heat to warm a space to be heated. A heat sensor is provided sensing the temperature within the radiant heater assembly for automatically disabling the heater elements upon exposure of the sensor to temperature in excess of a predetermined threshold temperature. A tip-over switch is provided for disabling the heater elements in resonse to predetermined tilting movement of the radiant heater assembly relative to a normal upright position. Alert indicators are provided for indicating disablement of the heater elements upon actuation of either the heat sensor or tip-over switch.

This is a continuation-in-part of our earlier copending application Ser.No. 07/000,311 filed Jan. 5, 1987 issued as U.S. Pat. No. 4,755,653 onJuly 5, 1988 which is a continuation of application Ser. No. 07/156,881filed 02/18/88, now abandoned, which is a continuation of applicationSer. No. 07/312,363 filed 02/14/89, now abandoned.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to heaters. More particularly, the presentinvention relates to a heater assembly that includes at least one alertindicator for signaling the operator that the heater has been disabledbecause of a tip-over condition.

In conventional electric heaters, it is known to provide an overheatsensor for disabling the heater in the event of an overheat condition.It is also known in such heaters to provide a tip-over switch thatdisables the heater in the event of a tip-over condition. In this typeof known heater, a conventional thermostat is normally included whichpermits the operator to select the ambient temperature at which theheater will turn on and off. Thus, the operator is generally able toselect the ambient temperature within the space to be heated.

One object of the present invention is to provide an alert system in anelectric heater that will signal the operator that an abnormal conditionexists with the heater. Advantageously, this alert system will signalthe operator that the heater has been disabled because of a tip-overcondition, thereby improving the ability of the operator to monitor theoperation of the heater. This alert system can also be used to signalthe operator that the heater has been disabled because of an overheatcondition.

According to the present invention, a heater assembly is provided thatincludes heater means for generating heat to warm a space to be heated.The heater assembly also includes sensor means for sensing temperaturewithin the heater assembly. Alert means is provided for indicatingdisablement of the heater means. Tip-over means is provided foractivating the alert means in response to predetermined tilting movementof the heater assembly relative to a normal upright position.

Overheat means can also be provided for automatically disabling theheater means upon exposure of the sensor means to a temperature inexcess of a predetermined threshold temperature. The overheat means canalso trigger the alert means to signal disablement of the heater means.

One feature of the foregoing structure is that alert means is providedfor indicating disablement of the heater means upon actuation of theoverheat means. One advantage of this feature is that the operator isalerted when an abnormal condition exists within the heater.

Another feature of the foregoing structure is that tip-over means isprovided for activating the alert means independent of actuation of theoverheat means in response to predetermined tilting movement of theradiant heater assembly relative to a normal upright position. Oneadvantage of this feature is that the single alert means can beactivatable independently by the tip-over means and the overheat meansto alert the operator of an abnormal condition.

In preferred embodiments of the present invention, the alert meansincludes a light and a buzzer that are both activated upon actuation ofthe overheat means or, or upon actuation of the tip-over means.Provision of such an alert system advantageously enables an operator tomonitor the operation of the heater during use and determine, by sightor sound, whether the heater has been disabled by normal operation ofthe thermostat or by operation of either the overheat or tip-over means.

Another feature of the foregoing structure is that two types ofindicators are provided for alerting the operator of an abnormalcondition. One advantage of this feature is that the operator isprovided both with an aural signal and a visual signal of an abnormalheater operation condition.

Additional objects, features, and advantages of the invention willbecome apparent to those skilled in the art upon consideration of thefollowing detailed description of a preferred embodiment exemplifyingthe best mode of carrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the accompanyingdrawings which diagrammatically illustrate two preferred embodiments foran electrical circuit for use in a heater in accordance with theinvention.

FIG. 1 shows a circuit for a heater using the present invention havingtwo tip-sensitive switches.

FIG. 2 shows an alert circuit for a heater using the present inventionhaving a single tip-sensitive switch.

FIG. 3 shows a heater circuit for use with the circuit of FIG. 2.

DETAILED DESCRIPTION OF THE DRAWINGS

A heater assembly 10 is shown in FIGS. 1 and 3 to include a conventionalheater section 12. The heater section 12 includes a first heater element14 and a second heater element 16. The first heater element 14 andsecond heater element 16 are controlled by a heat selector switch 20.The heat selector switch 20 is a conventional three position selectorswitch that includes a switch arm 22. The switch arm 22 is connected toa first pole L1 of the incoming power supply. The switch arm 22 ismovable to any of three positions to control the function of the heatersection 12. When the switch arm 22 is in the center-off position (asillustrated in the drawing), no power is being delivered to the heatersection 12. When the switch arm 22 is moved to be in contact with theterminal 23, power is supplied to both the second heater element 16 andthe first heater element 14 to produce a lower amount of heat from theheater section 12. When the switch arm 22 is moved to contact theterminal 24, only the first heater element 14 receives power, whichresults in a higher heat output from the heater section 12.

The heater assembly 10 also includes a fan motor 26. One terminal ofmotor 26 is connected to terminal 24 to lie in parallel with firstheater element 14 and also to the terminal 23 to lie in series withsecond heater element 16. The motor 26 receives power whenever the heatselector switch 20 is in either of the two "on" positions. The motor 26drives a fan (not shown) that conventionally circulates air around andthrough the reflector portion (not shown) of the heater assembly 10 toincrease the heating capability and effectiveness of the heater assembly10. The other terminal of the motor 26 is coupled through a conventionalthermostat 30 to a second pole L2 of the incoming power supply.

The thermostat 30 shown in both FIGS. 1 and 2 operates in a conventionalmanner to control the actuation of motor 26 and heater section 12,thereby controlling the temperature at which the space to be heated (notshown) is maintained. The thermostat 30 includes a pair of contacts 31that are adjusted by a conventional thermostat control 33. In a knownmanner, the thermostat control 33 adjusts the orientation of thecontacts 31 so that the contacts 31 will close to provide power to themotor 26 and heater section 12 when the temperature within the space tobe heated falls below a temperature selected by the thermostat control33. Likewise, the contacts 31 will open when the temperature within thespace to be heated rises above the preselected temperature.

In FIG. 1, the thermostat 30 also includes pendulum means 32 thatcooperates with the contacts 31 to function as a tip switch to open thecontacts 31 should the heater assembly 10 be tipped beyond a preselectednumber of degrees, thereby removing power from the motor 26 and theheater section 12. The thermostat 30 is connected to the second pole L2to complete the circuit through the heater section 12 and motor 26. Inaddition, a "power on" light 28 is provided that is coupled between thesecond pole L2 and the motor 26 to indicate to the operator that theheat selector switch 20 is in one of the two "on" positions.

The heater assembly 10 shown in FIG. 1 is configured to include alertmeans 34 to indicate to the operator that the heater section 12 has beendisabled either because of an overheat condition or because of atip-over condition. The alert means 34 includes a light 36 and a buzzer38 that are connected in parallel between second pole L2 and an overheatcontrol unit 42. The overheat control unit 42 includes a conventionalsingle pole, double throw temperature control switch having threeterminals 43, 44, and 45 and a switch-activating overheat sensor 47 forsensing temperature in heater assembly 10. First terminal 43 is coupledto first pole L1, second terminal 44 is connected to the switch arm 22of the heat selector switch 20, and third terminal 45 is connected tothe common terminal of the light 36 and the buzzer 38. A switch arm 46is coupled to the first terminal 43, and moves between the secondterminal 44 and the third terminal 45 in response to an instruction fromthe overheat sensor 47. It will be understood that, in otherembodiments, the switch arm 46 could be configured to function as theoverheat sensor, eliminating the necessity of a separate overheat sensor47.

As illustrated in FIG. 1, when the switch arm 46 is in contact with thesecond terminal 44, power is supplied to the heat selector switch 20 forselectively powering the heater section 12. However, when the overheatsensor 47 in overheat control unit 42 is exposed to temperatures withinthe heater assembly 10 in excess of a predetermined thresholdtemperature, the switch arm 46 moves in a known manner to a position incontact with the third terminal 45. This movement removes power from theheat selector switch 20 to disable the heater section 12. It will beunderstood that it is necessary to disable the heater section 12 shouldan over-temperature condition occur within the heater assembly 10.

To provide an indication to the operator that the heater section 12 hasbeen disabled, FIG. 1 shows a pair of normally open signaling circuitsbeing provided, each signaling circuit including the alert means 34(illustratively light 36 and buzzer 38). The first signaling circuitincludes overheat control unit 42 and alert means 34 while the secondsignaling circuit includes tip switch 48 and alert means 34. Theoverheat control unit 42, heat selector switch 20, heater section 12,and thermostat 30 cooperate in series to form a normally closed heatingcircuit.

When the switch arm 46 shown in FIG. 1 moves into contact with the thirdterminal 45, the heating circuit is opened to disable heater section 12.Simultaneously, the normally open first signaling circuit is closed toprovide power to the light 36 and buzzer 38 to provide both an aural andvisual indication to the operator that the heater section 12 has beendisabled and that an abnormal condition exists within the heaterassembly 10. The first circuit means includes the overheat control unit42, as well as the first signaling circuit just described.

In addition, second circuit means is provided as shown in FIG. 1 foractivating the alert means 34 whenever the heater assembly 10 is tiltedto a predetermined position relative to the normal upright position. Thesecond circuit means includes a normally open tip switch 48 thatincludes normally open contacts 49 and pendulum means 51. One terminalof the tip switch 48 is connected to first pole L1, while the otherterminal is connected to the third terminal 45 of the overheat controlunit 42. When the heater assembly 10 is tilted through a preselectedangle, the pendulum means 51 pivots to close the normally open contacts49, thereby closing the second circuit means. Thus, the second circuitmeans, including the tip switch 48, operates in parallel with theoverheat control unit 42 to provide a second signaling circuit whichactivates the alert means 34, thereby alerting the operator that anabnormal condition exists with the heater assembly 10 (in this case anabnormal orientation of the heater assembly 10 relative to a normalupright position). Due to the novel structure of heater assembly 10, thealert means 34 is actuatable by second signaling circuit in a mannerwholly independent of the operation of the overheat control unit 42.

Thus, because the second circuit means cooperates independently of theposition of the switch arm 46 in the overheat sensor 42, the alert means34 can be activated by either an overheat condition within the heaterassembly 10 or by an abnormal orientation of the heater assembly 10relative to a normal upright position. Therefore, only one alert means34 is necessary to provide an indication to the operator of either ofthese abnormal condition.

FIG. 2 shows an alternative circuit 11 for supplying power andindicating faulty operation of the heater assembly 12 shown in FIG. 3.The terminals T2 and T4 of FIG. 3 are intended to be connected toterminals T2 and T4 of FIG. 2 respectively. Terminal T2 is connected tosecond pole L2 of the power plug. The terminal T4 is connected to firstpole L1 of the power plug in series with the thermostat 30, a tip-switch52 and an overheat control unit 42'. The function and operation of thethermostat 30 is unchanged from the previously discussed operationrelating to FIG. 1.

The circuit 11 includes a "power on" light 28' similar in operation to"power on" light 28 shown in FIG. 1 It is to be noted, however, that"power on" light 28' will be illuminated at any time that power isapplied to poles L1 and L2 of the plug supplying power to circuit 11.The illumination of "power on" light 28' does not depend on the positionof switch arm 22 of switch 20 shown in FIG. 3 which is unlike "power on"light 28 of FIG. 1 which is illuminated only when switch arm 22 issituated in contact with either terminals 23 or 24.

The circuit 11 of FIG. 2 also includes an alert means 34' including alight 36' and a buzzer or other audible alarm 38'. The operation of thealert means 34' is controlled by a solid state switch 53, which can be aSCR or triac, resistors 54, 55, and 56, and capacitor 57. The resistancevalue of resistors 54 and 55 should be selected so as to be much greaterthan the contact resistances present in both tip-switch 52 and overheatcontrol unit 42'. This selection of resistances assures that virtuallyno current will flow through resistances 54 and 55 so long as controlunit 42' and switch 52 are in a closed position. Thus so long as controlunit 42' and switch 52 are closed, a negligible potential drop willexist between pole L1 and thermostat 30. In such situation, a potentialdrop will exist across resistor 56 approximately equal to the total linevoltage across poles L1 and L2 of the plug.

The resistance of resistor 56 is selected to be much larger than theresistance of either heater element 14 or heater element 16 of heatersection 12 shown in FIG. 3. This assures that when the switch arm 22 ofswitch 20 is connected to either terminal 23 or terminal 24,substantially all of the current will flow through the circuit shown inFIG. 3 so long as the contacts 31 of thermostat 30 remain closed. Inaddition, the resistance values of resistors 54, 55, and 56 are selectedso that under certain conditions, discussed below, the series ofresistors 54, 55, and 56 will construct a potential divider providing atriggering voltage to trigger input 58 of switching device 53. A typicalvalue for resistor 54 is 10,000 ohms while a typical value for resistors55 and 56 is 100,000 ohms each. The capacitor of 57 acts together withthe resistor 54 in a conventional manner as a surge suppressor toprevent undesired triggering of the switching device 53 due to suddenvariations in line voltage across poles L1 and L2 of the plug.

The overheat control unit 42' includes a switch activating overheatsensor and switch 46' similar to that disclosed in connection withFIG. 1. The switch 46' included in the overheat control unit 42' needonly be a single pole, single throw switch which is normally closedduring conventional operation but opens in the event that excessive heatis sensed by the control unit 42'. In the event that an overheatcondition is sensed, the switch arm 46' moves from its illustratednormally closed position to an open position. With the switch 46' in anopen position, a potential develops across resistance 54 sufficient totrigger the switching device 53 into conduction thereby causing thealarm means 34' to operate.

Tip switch 52 which is illustrated as a mercury switch is arranged tonormally conduct electricity when the heater containing the circuit 11is in its normal upright attitude. In the event that the heater istipped, the mercury within the mercury switch will be displaced in aknown manner so as to open the contacts of the switch. The effect of theopening of the contacts of switch 52 will be the same as the opening ofswitch 46' previously discussed. In addition to triggering the alarmmeans 34', the opening of either tip switch 52 or overheat control unit42' will cause the current available to the heater section 12 to bediminished to nearly zero thereby reducing any inherent hazard whichmight be presented by the continued operation of the heater section 12.

The heater assembly 10 of the present invention is able to provide anaural and visual warning to the operator that either of two abnormalconditions exist within the heater assembly 10. The overheat controlunit 42, 42' operates both to disable the heater section 12 and toactivate the alert means 34, 34'. In addition, the tip switch 48, 52operates independently of the overheat control unit 42, 42' to activatethe alert means 34, 34' whenever the heater assembly 10 is tilted to anabnormal orientation. When the overheat control unit 42 activates todisable the heater section 12, the activation of the alert means 34provides an indication to the operator that the heater assembly 10 hasbeen turned off due to an abnormal condition within the heater assembly10, and not because of the normal functioning of the thermostat 30.

Although the invention has been described in detail with reference tothe illustrated preferred embodiments and specific examples, variationsand modifications exist within the scope and spirit of the invention asdescribed and defined in the following claims.

What is claimed is:
 1. An alert system for monitoring the operation of aheater assembly, the heater assembly having heater means for generatingheat to warm a space to be heated, thermostatic means for sensing thetemperature of the space to be heated, and switch means responsive tothe thermostatic means for controlling the operation of the heatermeans, the alert system comprising:a signaling means for emitting ahumanly perceivable signal, signal switch means connected to thesignaling means for enabling the signaling means to emit the signal,tilt sensing means for disabling the heater means in response to apredetermined tilting movement of the heater assembly relative to anormal upright position, and circuit means connecting the tilt sensingmeans and the signal switch means for causing the signal switch means toenable the signaling means upon disablement of the heater means by thetilt sensing means regardless of the temperature sensed by thethermostatic means.
 2. The alert system of claim 1 further comprisingoverheat control means for disabling the heater means upon elevation ofthe temperature in the heater assembly to a temperature in excess of apredetermined threshold temperature, the overheat control means beingconnected to said circuit means to enable the signaling means upondisablement of the heater means.
 3. The alert system of claim 1 whereinthe signaling means includes at least one means for issuing an audiblesignal to a person in proximity to the heater assembly.
 4. The alertsystem of claim 3 wherein the signaling means further includes lightmeans for providing a visible signal to a person in proximity to theheater assembly.
 5. A heater assembly comprising heat generating meansfor generating heat to warm a space to be heated, thermostatic means forsensing the temperature of the space to be heated, and switch meansresponsive to the thermostatic means for controlling the operation ofthe heater means, tilt means for sensing a predetermined tiltingmovement of the heater relative to a normal upright orientation, thetilt means including circuit means which operates in response to suchtilting movement to disable the heat generating means, and alert meansfor indicating a tilting movement of the heater means sufficient todisable the heater means, the alert means being operable regardless ofthe temperature sensed by the thermostatic means.
 6. The heater assemblyof claim 5 further comprising temperature sensitive means for disablingthe heat generating means upon exposure to a temperature in excess of apredetermined threshold, the temperature sensitive means coupled to thealert means for activating the alert means upon disablement of theheater means.
 7. The heater assembly of claim 5 further comprising aircirculating means for circulating air by the heat generating means. 8.The heater assembly of claim 7 further comprising circuit meansconnecting the air circulating means to the heat generating means forcausing the air circulating means to be disable with the disabling ofthe heat generating means.
 9. An electric heater assembly operable in anormal upright orientation and susceptible to a tip-over conditioncomprising heater means for generating heat to warm a space to beheated, thermostat means for sensing the temperature in the space to beheated for controlling the heat generated by the heater means, overheatmeans coupled to the heater means for disabling the heater means uponsensing a temperature in the heater assembly in excess of apredetermined threshold temperature, tip-over means for disabling theheater means upon sensing a predetermined tilting movement of the heaterassembly relative to the normal upright position, and alert means forindicating disablement of the heater means upon actuation of either theoverheat means or the tip-over means, the alert means being operableregardless of the temperature sensed by the thermostat means.
 10. Theheater assembly of claim 9 wherein the alert means includes audiblemeans for issuing an audible signal to a person in proximity to theheater assembly.
 11. The heater assembly of claim 9 wherein the alertmeans includes light means for providing a visible signal to a person inproximity to the heater assembly.
 12. The heater assembly of claim 9wherein the heater means comprises an electrical resistance heating unitand a fan for circulating air by the resistance heating unit, both theresistance heating unit and fan being subject to disablement by theoverheat means and the tip-over means.
 13. An alert system formonitoring operation of an electric heater assembly, the heater assemblybeing operable in a normal upright orientation but susceptible to atip-over condition, and having heater means for generating heat to warma space to be heated, thermostatic means for sensing the temperature ofthe space to be heated, and switch means responsive to the thermostaticmeans for controlling the operation of the heater means, the alertsystem comprising first circuit means for automatically disabling theheater means upon elevation of the temperature within the heaterassembly to a temperature in excess of a predetermined thresholdtemperature, second circuit means for automatically disabling the heatermeans in response to a predetermined tilting movement of the heaterassembly relative to the normal upright position, and signaling meansoperable regardless of the temperature sensed by the thermostat means,for indicating the disablement of the heater means by one of the firstand second circuit means.
 14. The alert system of claim 13 wherein thesignaling means comprises an audible signal generating means forgenerating a signal audible to a person situated in the space to beheated.
 15. The alert system of claim 14 wherein the signaling meanscomprises light means for providing a signal visible to a personsituated in the space to be heated.
 16. The alert system of claim 13further comprising switch means responsive to the first and secondcircuit means for coupling a source of power to the signaling means. 17.The alert system of claim 16 further comprising means coupled to theswitch means for responding to either of the first and second circuitmeans to develop a potential for operating the switch means.
 18. Thealert system of claim 13 further comprising power signal means forsignaling that power has been applied to the heater assembly.
 19. Thealert system of claim 18 wherein the power signal means and the firstcircuit means are coupled together such that disabling of the heatermeans by the first circuit means will simultaneously remove power fromthe power signal means.
 20. The alert system of claim 13 furthercomprising thermostatic means responsive to the temperature in the spaceto be heated for controlling the operating of the heater means, thefirst and second circuit means being operable independent of thetemperature of the space to be heated.